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Hip Roof Load Info.

03-18-2011, 12:33 AM

I have a two car garage 20' wide by 22' long with 7' tall 2X4 side walls. It has a 4/12 pitch hip roof that's about 22' X 24' counting the overhangs. The 4 hip beams are 2X8's and about 16' long. The ridge board is a 2X6 & just over 4' long. There are 8 common rafters 2X6's at about 11' 6” each, (three on each side of the ridge board & one at either end) The rest of the framing is 2X6 jack rafters from the hip beams to the walls. All framing including the walls is 24” O/C.

Giving the construction information on the garage can the ridge board & or rafters be reinforced to handle the weight of pulling a V8 engine?

the answer is yes, with a collar joist and some tie pieces and making it into a truss like member it would do it. the cost of a folding shop hoist would not cost one any more than the lumber and labor to do it,

but I would suggest to just get a harbor freight folding shop hoist,

there made in one ton and two ton versions, (I personally would go with the two ton unit),

they will work, do not over load as HF stuff is not made with much safety margin in there design,
many like the folding design for storage of the shop cranes, (Norther tools sell some thing similar),

currently they have a 20 percent off coupon,( I see it says some restrictions I do not know what they are),

I built my own shop hoist, but it can move around a Little and not have to move the car or truck under the engine to aligned it (I have pulled engines both ways, and using a shop hoist or crane is far superior, IMO, to a chain or come-a-long hanging from some beam, (when moving the engine across the floor, lower to just clear the floor do not leave it handing up high in the air), a swinging V8 engine is a lot of weight and can easily pull a shop hoist over, (never have had it happen, but worth to use caution),

Push sticks/blocks Save Fingers
~~~~~~~~~~~~~~~~~~~
"The true measure of a man is how he treats someone who can do him absolutely no good."
attributed to Samuel Johnson
~~~~~~~~~~~~~~~~~~~
PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

I built my own shop hoist, but it can move around a Little and not have to move the car or truck under the engine to aligned it (I have pulled engines both ways, and using a shop hoist or crane is far superior, IMO, to a chain or come-a-long hanging from some beam,

Yea I looked at those; But like yourself I could also make my own. I have about 100' of 2-1/2” OD X 1/4” Wall DOM (Drawn Over Mandrel) tubing that I got free from a job site! I also have access to a welder, torches, & metal saw at work.

I agree with you about the moving the vehicle verses a mobile hoist
but my main reason for not wanting a mobile shop hoist is lack of floor space! My garage is set-up mainly for woodworking with everything on wheels which is moved to the sides so that I can still get a car in the garage.

I insulated the walls & covered them with 1/2” OSB last fall & I'm currently planning out the framing for a ceiling. My plans are to also have an access panel in the center of the ceiling so the hoist would be up & out of the way when not needed. Also there will be several feet of storage space above the new ceiling & the hoist could help getting awkward items up there.

your a little narrower than the plan listed, so you would in theory be a some what stronger,
the first link listed, looks close to what I think one would want,
Note: the snow load, and figure the truss as a heavy snow load, (temporary load), on the third line down of the chart under 4/12 pitch, this design would hold 62 pounds per foot of combined, loads, so figure your standard is load is 15 that would give one about 47 pounds if applied equality across the roof, if placed on 24 inch centers, that would be about 90 pounds per foot, and at 24 foot that would a little over a ton, now I would beef up the bottom cord more than a single 2x6 as your not even in your load, your going to concentrated it, to one location, so you could still bust the bottom cord out of the rafter, so if one would double or even triple up the bottom cord at least the two/three webs (depending on your truss design), that are in the center, to support the concentrated weight,
(now for hoisting), I would derate it by at least Halve or even to 500 pounds, (which would still lift all but the heaviest of V8 engines),

unless your going to go to an engineer and have it figured and follow his plans I would signify derate any self or do it your self plans,

most engineered designs are done with machine rated lumber, and truss plates that have been machine tested in there stress and holding abilities, in a field built truss, one usually does not have that type of information and most of us do not have the formula or design knowledge to build a truss that could be certified, (or math ability to calculate its true load carrying capabilities)

so proceed at your own risk, regardless of what is done your responsible for your own decisions,

I know it can be done (lift a engine out of a truck) using a wood frame building as I have done it. (was it safe or how close to failure I was I do not know),

Push sticks/blocks Save Fingers
~~~~~~~~~~~~~~~~~~~
"The true measure of a man is how he treats someone who can do him absolutely no good."
attributed to Samuel Johnson
~~~~~~~~~~~~~~~~~~~
PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

Comment

A 2x6 ridge with 2x6 rafters would not be proper IMO. The ridge should be one size larger atleast......should have been a 2x8. when you cut rafters or jack rafters out of 2x6 and use a 2x8 ridge or better it gives you more material to nail your rafters to.

Comment

A 2x6 ridge with 2x6 rafters would not be proper IMO. The ridge should be one size larger atleast......should have been a 2x8. when you cut rafters or jack rafters out of 2x6 and use a 2x8 ridge or better it gives you more material to nail your rafters to.

On a 4/12 roof, the length of the plumb cut on the rafters would only be about 1/8" longer than the 5 1/2" of the 2x6. The ridge does nothing to the strength of the roof--only use is ease of holding the rafters in place during assembly.

Comment

On a 4/12 roof, the length of the plumb cut on the rafters would only be about 1/8" longer than the 5 1/2" of the 2x6. The ridge does nothing to the strength of the roof--only use is ease of holding the rafters in place during assembly.

I still would have used a 2x8. So the ridge does nothing now but to ease holding the rafters in place.......so nailing it is useless In hurricane country the ridge does plenty when the wind blows 150 mph.+

ADD> Where do you think the 2x8 hips connect? The ridge maybe? Think about it for a minute.

Comment

I agree that the 2x8 ridge with 2x6 rafters would be a better nailing surface, but I have seen many with out ridge boards and many with only 1x ridge boards,

think about trusses they do not normally use any ridge type boards, if they do there only spacers, until the roof deck is put on, most likely the ridge in this case was just used to help in the construction of the roof, not actually a true structural component of the building when it was fully constructed, (but was nearly necessary in the construction phase of it) but it is surprising that the hips being 2x8, the short ridge was not the same, (probably had more 2x6 than 2x8's).

Push sticks/blocks Save Fingers
~~~~~~~~~~~~~~~~~~~
"The true measure of a man is how he treats someone who can do him absolutely no good."
attributed to Samuel Johnson
~~~~~~~~~~~~~~~~~~~
PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

Comment

I still would have used a 2x8. So the ridge does nothing now but to ease holding the rafters in place.......so nailing it is useless In hurricane country the ridge does plenty when the wind blows 150 mph.+

ADD> Where do you think the 2x8 hips connect? The ridge maybe? Think about it for a minute.

The odds are that the hips do not even touch the ridge. By the OP's description, there is a rafter at each end of the ridge (going to each side) and one on each end of the ridge. In 99.9% of the time the common rafters are put up first and then the hips and jacks. Unless this was one of the .1%, the hips never touch the ridge. On another subject relating to the OP's post, if the garage is 20'x22' as stated, the ridge should only be 2' long. Something doesn't add up.

Comment

keep it simple. Just run some vert. 4x4s witha 2x4 ledger supporting a 4x10 across. Temp tie into ceiling rock with some simpson hardware. Remember a carrying header works click above the ceiling with simpson ties and You have a clean ceiling after removing a partition. I have removed roof sheathing and shingles and slid a big stick into the attic above.

I can build anything You want , if you draw a picture of it , on the back of a big enough check .